148 lines
		
	
	
		
			4.5 KiB
		
	
	
	
		
			Python
		
	
	
			
		
		
	
	
			148 lines
		
	
	
		
			4.5 KiB
		
	
	
	
		
			Python
		
	
	
| # -*- coding: utf-8 -*-
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| # Copyright 2014-2016 OpenMarket Ltd
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| # Copyright 2020 The Matrix.org Foundation C.I.C.
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| #
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| # Licensed under the Apache License, Version 2.0 (the "License");
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| # you may not use this file except in compliance with the License.
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| # You may obtain a copy of the License at
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| #
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| #     http://www.apache.org/licenses/LICENSE-2.0
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| #
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| # Unless required by applicable law or agreed to in writing, software
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| # distributed under the License is distributed on an "AS IS" BASIS,
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| # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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| # See the License for the specific language governing permissions and
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| # limitations under the License.
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| import itertools
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| import random
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| import re
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| import string
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| from collections import Iterable
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| 
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| import six
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| from six import PY2, PY3
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| from six.moves import range
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| 
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| from synapse.api.errors import Codes, SynapseError
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| 
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| _string_with_symbols = string.digits + string.ascii_letters + ".,;:^&*-_+=#~@"
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| 
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| # https://matrix.org/docs/spec/client_server/r0.6.0#post-matrix-client-r0-register-email-requesttoken
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| # Note: The : character is allowed here for older clients, but will be removed in a
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| # future release. Context: https://github.com/matrix-org/synapse/issues/6766
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| client_secret_regex = re.compile(r"^[0-9a-zA-Z\.\=\_\-\:]+$")
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| 
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| # random_string and random_string_with_symbols are used for a range of things,
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| # some cryptographically important, some less so. We use SystemRandom to make sure
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| # we get cryptographically-secure randoms.
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| rand = random.SystemRandom()
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| 
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| 
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| def random_string(length):
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|     return "".join(rand.choice(string.ascii_letters) for _ in range(length))
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| 
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| 
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| def random_string_with_symbols(length):
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|     return "".join(rand.choice(_string_with_symbols) for _ in range(length))
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| 
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| 
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| def is_ascii(s):
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| 
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|     if PY3:
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|         if isinstance(s, bytes):
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|             try:
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|                 s.decode("ascii").encode("ascii")
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|             except UnicodeDecodeError:
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|                 return False
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|             except UnicodeEncodeError:
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|                 return False
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|             return True
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| 
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|     try:
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|         s.encode("ascii")
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|     except UnicodeEncodeError:
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|         return False
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|     except UnicodeDecodeError:
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|         return False
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|     else:
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|         return True
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| 
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| 
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| def to_ascii(s):
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|     """Converts a string to ascii if it is ascii, otherwise leave it alone.
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| 
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|     If given None then will return None.
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|     """
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|     if PY3:
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|         return s
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| 
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|     if s is None:
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|         return None
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| 
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|     try:
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|         return s.encode("ascii")
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|     except UnicodeEncodeError:
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|         return s
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| 
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| 
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| def exception_to_unicode(e):
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|     """Helper function to extract the text of an exception as a unicode string
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| 
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|     Args:
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|         e (Exception): exception to be stringified
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| 
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|     Returns:
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|         unicode
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|     """
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|     # urgh, this is a mess. The basic problem here is that psycopg2 constructs its
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|     # exceptions with PyErr_SetString, with a (possibly non-ascii) argument. str() will
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|     # then produce the raw byte sequence. Under Python 2, this will then cause another
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|     # error if it gets mixed with a `unicode` object, as per
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|     # https://github.com/matrix-org/synapse/issues/4252
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| 
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|     # First of all, if we're under python3, everything is fine because it will sort this
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|     # nonsense out for us.
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|     if not PY2:
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|         return str(e)
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| 
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|     # otherwise let's have a stab at decoding the exception message. We'll circumvent
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|     # Exception.__str__(), which would explode if someone raised Exception(u'non-ascii')
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|     # and instead look at what is in the args member.
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| 
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|     if len(e.args) == 0:
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|         return ""
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|     elif len(e.args) > 1:
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|         return six.text_type(repr(e.args))
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| 
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|     msg = e.args[0]
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|     if isinstance(msg, bytes):
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|         return msg.decode("utf-8", errors="replace")
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|     else:
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|         return msg
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| 
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| 
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| def assert_valid_client_secret(client_secret):
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|     """Validate that a given string matches the client_secret regex defined by the spec"""
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|     if client_secret_regex.match(client_secret) is None:
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|         raise SynapseError(
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|             400, "Invalid client_secret parameter", errcode=Codes.INVALID_PARAM
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|         )
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| 
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| 
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| def shortstr(iterable: Iterable, maxitems: int = 5) -> str:
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|     """If iterable has maxitems or fewer, return the stringification of a list
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|     containing those items.
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| 
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|     Otherwise, return the stringification of a a list with the first maxitems items,
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|     followed by "...".
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| 
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|     Args:
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|         iterable: iterable to truncate
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|         maxitems: number of items to return before truncating
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|     """
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| 
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|     items = list(itertools.islice(iterable, maxitems + 1))
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|     if len(items) <= maxitems:
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|         return str(items)
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|     return "[" + ", ".join(repr(r) for r in items[:maxitems]) + ", ...]"
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